- add host field on flushing
- add host field on flushing

tinglinux/logstash-kafka,tinglinux/logstash-kafka,joekiller/logstash-kafka,Aloomaio/logstash-kafka,Aloomaio/logstash-kafka,joekiller/logstash-kafka,opentable/logstash-kafka,opentable/logstash-kafka